Spend limit
A spend limit is the most money a service may charge you in a month, set by you.
In a simple example
You set 10 dollars as the monthly limit. When the AI service reaches it, it stops instead of charging more.
Why it matters to you
A mistake in a loop can use thousands of requests overnight, and a limit is what stops the bill.
Do not confuse with
A spend limit is about money. A rate limit is about how fast requests come.